441,567 research outputs found
The entanglement of purification
We introduce a measure of both quantum as well as classical correlations in a
quantum state, the entanglement of purification. We show that the (regularized)
entanglement of purification is equal to the entanglement cost of creating a
state asymptotically from maximally entangled states, with negligible
communication. We prove that the classical mutual information and the quantum
mutual information divided by two are lower bounds for the regularized
entanglement of purification. We present numerical results of the entanglement
of purification for Werner states in .Comment: 12 pages RevTex, 1 figure, to appear in JMP special issue on quantum
information. v3 contains additional references, motivation, and a small
change in the figur
Lower Bounds for Attainable Fidelity in Entanglement Purification
We derive lower bounds for the attainable fidelity of standard entanglement
purification protocols when local operations and measurements are subjected to
errors. We introduce an error parameter which measures the distance between the
ideal completely positive map describing a purification step and the one in the
presence of errors. We derive non--linear maps for a lower bound of the
fidelity at each purification step in terms of this parameter.Comment: 11 page
Entanglement of Purification and Multiboundary Wormhole Geometries
We posit a geometrical description of the entanglement of purification for
subregions in a holographic CFT. The bulk description naturally generalizes the
two-party case and leads to interesting inequalities among multi-party
entanglements of purification that can be geometrically proven from the
conjecture. Further, we study the relationship between holographic
entanglements of purification in locally-AdS3 spacetimes and entanglement
entropies in multi-throated wormhole geometries constructed via quotienting by
isometries. In particular, we derive new holographic inequalities for
geometries that are locally AdS3 relating entanglements of purification for
subregions and entanglement entropies in the wormhole geometries.Comment: 23 pages, 12 figures; v2 added references; v3 fixed inequality
direction in Eq.(2), expanded discussion - reflects published versio
Entanglement purification of multi-mode quantum states
An iterative random procedure is considered allowing an entanglement
purification of a class of multi-mode quantum states. In certain cases, a
complete purification may be achieved using only a single signal state
preparation. A physical implementation based on beam splitter arrays and
non-linear elements is suggested. The influence of loss is analyzed in the
example of a purification of entangled N-mode coherent states.Comment: 6 pages, 3 eps-figures, using revtex
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